Bhagavad Gita Chapter 11, Verse 18
त्वमक्षरं परमं वेदितव्यं त्वमस्य विश्वस्य परं निधानम् | त्वमव्ययः शाश्वतधर्मगोप्ता सनातनस्त्वं पुरुषो मतो मे ||
tvam akṣaraṁ paramaṁ veditavyaṁ tvam asya viśvasya paraṁ nidhānam tvam avyayaḥ śāśvata-dharma-goptā sanātanas tvaṁ puruṣo mato me
You are the imperishable, the supreme to be known. You are the ultimate resting place of this universe. You are the eternal protector of eternal dharma. You are the ancient Supreme Person—this is my understanding.
Arjuna expresses his understanding of Krishna's true nature. 'Tvam akṣaraṁ paramaṁ veditavyaṁ'—You (tvam) are the imperishable (akṣaram), the supreme (paramam) to be known (veditavyam). 'Tvam asya viśvasya paraṁ nidhānam'—You are the ultimate resting place (paraṁ nidhānam) of this universe (asya viśvasya). 'Tvam avyayaḥ śāśvata-dharma-goptā'—You are the imperishable (avyayaḥ), the eternal protector (śāśvata-dharma-goptā) of eternal dharma. 'Sanātanas tvaṁ puruṣo mato me'—the ancient (sanātanaḥ) Supreme Person (puruṣaḥ), this is my understanding (mato me). Arjuna has grasped Krishna's true nature: imperishable, supreme, the ultimate abode, protector of dharma, the eternal Supreme Person. This verse shows Arjuna's deep understanding of what he's witnessing.